Change some section names

Signed-off-by: Dave Rodgman <dave.rodgman@arm.com>
diff --git a/docs/3.0-migration-guide.md b/docs/3.0-migration-guide.md
index 0e156b4..b9200ac 100644
--- a/docs/3.0-migration-guide.md
+++ b/docs/3.0-migration-guide.md
@@ -16,7 +16,7 @@
 - Removal of functions previously marked as deprecated.
 
 
-## Tooling
+## General changes
 
 ### Introduce a level of indirection and versioning in the config files
 
@@ -493,7 +493,7 @@
 
 
 
-## The ALT interface
+## Changes that only affect alternative implementations
 
 ### Internal / alt-focused headers were moved to a private location